Patent GB-813674-A (GB)
Title: An apparatus for discharging a predetermined amount of a liquid
IPC: G01F3/38
Filed: 1957-08-28
Abstract: 813,674. Delivering measured quantities of liquids. TARUKAWA, T. Aug. 28, 1957 [Aug. 29, 1956; June 11, 1957; July 12, 1957], No. 27102/57. Class 106(5) Apparatus for dispensing measured quantities of liquids comprises a tank 1 in which a float 19 and weight 22 are movable up and down on a rod 103, Fig. 13, a discharge valve 21 which is closed by the fall of the float and weight at the end of liquid discharge, a filling valve 25 and a bell-crank B1 with a weight W1 on one arm which is movable to one side of a vertical position by the fall of the weight and float to close the discharge valve and to the other side of the vertical by the movement of means for opening the discharge valve. As shown in Fig. 13, the float and weight, in the discharged condition of the tank, rest on a plate 16 fixed to the rod 103 and bearing on a lever 108 having a resilient member 117 connected to a valve 21 with a cruciform stem 21a and the rod 103 is linked to the filling valve by a lever 105, the latter being connected to the bell-crank Bl by a weighted lever 113 and link 116. For raising the discharge valve, the lever 108 is connected to a handle 118 by the link 107, a weighted lever 114 and a link 115 which is also connected to a weighted bell-crank B2. In the filling condition of the tank as shown in Fig. 13, both bell-cranks ensure that the discharge valve is held closed but, as the float and weight rise to meet a stop 104, the rod 103 is gradually raised until the bell-crank Bl falls suddenly over to the other side of the vertical and securely closes the filling valve. When the handle 118 is subsequently pulled; the discharge valve 21 is opened and is held open by the toppling-over of the bell-crank B2. Near the end of the discharge of the measured quantity, the increase in speed of the fall of the liquid in the basin 23 causes the weight and float to push the plate 16 and valve 21 forcibly into the closed position and the bell-cranks are returned to their initial positions, the lowering of the rod 103 then opening the filling valve. In a modification, the rod 103 is connected by a chain to the lever 105 and a second float is connected to the lever so that, as the float 19 rises and meets a stop fixed to the tank side at a lower level than the stop 104, the chain becomes sufficiently slack to allow the second float to rise and close the filling valve when the liquid level in the tank reaches the required level. By adjustment of the weights W1 and W2 along the arms of the bell-cranks, the point at which they act and, therefore, the liquid level is altered. In further modifications, the filling valve is operated by a single solenoid or by a pair of opposed solenoids, m1, m2, Fig. 1, under'the control of a pushbutton switch PS and solenoid m3 for initiating the discharge, a switch S1 controlled by the bellcrank B1 and switch S2 controlled by a float 27 at the top of the tank. In the filling position shown, the solenoid m2 is energized through the closed switch S1 and the filling valve is held open. When the liquid level rises sufficiently to move the float 27 to close the switch S2, the solenoid m1 is energized and exerts sufficient force to overcome the solenoid m2 and close the filling valve. On initiating the discharge by means of the pushbutton PS, the bell-crank B1 is moved to allow the switch S1 to remain open until the final fall of the float 19 and weight 22 restores the bell-crank to its original position and the filling valve is opened by the closing of the switch Sl and energizing of the solenoid m2. The magnet m1 may alternatively be of the same power as the magnet m2 and be held de-energized for a period under the control of a timing device. The valve 25 may be operated by a reversible electric motor instead of solenoids and may have a third branch leading back to the input side of a pump, the motor for which may be switched off and on by the movement of the valve. The float-controlled switch S2 may be operated by a pair of spaced electrodes which are short-circuited by the liquid when it rises to the required level in the tank. The required level in the tank may be adjusted by varying the position of the switch S2, either by moving the body 29 of the switch or by varying the position of the float 27. As shown in Fig. 6, the contact-carrying rod 28 of the float is supported in a tube 39 which can be adjusted vertically by a handle 49 and a rack and pinion 47 and is held in adjusted position by a spring- operated clamp 41 released by a pedal 55, switch S5 and solenoid m5. A similar adjustment for the switch body by means of a wire instead of a rack and pinion drive and a mechanical gear-driven adjustment for the tube 39 are also described. Automatic discharging on closure of the filling valve combined with either manual or automatic control of therefilling may be provided.